Just restarting (which is turning it off and back on) wouldn't do that. However, if you 'reset' it, which is to make the phone return to the original OS, that can wipe some or all things, depending on which version of a reset was done.
If it was something after just restarting (turning off and on) the phone, the info below 'may' be of some help. If, however, you did a 'reset' then there is no way to get the files back.
While there is no guaranty that you can get them back. Deleted does mean deleted. There are a few apps/programs out there that 'may' be able to help you recover the data.
A few of the programs you could try would be... DiskDigger, MobiSaver, Android-Recovery and Tenorshare. They are all data recovery apps/programs. There are many others out there, so check around and see which you would rather try. There is also one called RECUVA, that I have heard is free, which you could try.
One important note though, most of these programs are not free. They may say they are "free" or have "Free Trials" and "Free Downloads". Yet to actually recover your data, and get your files back, you may be have to purchase the program/app. Just so you know.
NOTE: For future reference, I really would suggest backing up your data to a computer or cloud. Often. Better to spend the time doing that, rather than to be out all that stuff if the phone dies, things get deleted/erased or it gets stolen.